The present invention is directed to phase change or hot-melt ink compositions containing a colorant, a vehicle and a gelling agent component, and, more specifically, the present invention relates to hot melt inks with for example, a melting point of between about 25.degree. C. and about 150.degree. C., and preferably from about 30.degree. C. to about 70.degree. C., and which inks are especially useful for acoustic ink printing processes and apparatuses, reference, for example, U.S. Pat. No. 5,121,141, U.S. Pat. No. 5,111,220, U.S. Pat. No. 5,128,726, U.S. Pat. No. 5,371,531, the disclosures of which are totally incorporated herein by reference, including especially acoustic ink processes as illustrated in a number of the aforementioned copending applications and patents, such as an acoustic ink printer for printing images on a record medium.
More specifically, the phase change inks of the present invention are comprised of a colorant such as a dye or pigment, a vehicle such as a liquid, a solid hydrocarbon or wax, or mixture of a liquid and solid vehicle, and other known vehicles, and a gelling agent as illustrated herein, which primarily causes the ink to gel at a temperature of for example, from about 20.degree. C. to about 100.degree. C., and more specifically about 40.degree. C. to about 90.degree. C. (about to about includes all values in between throughout). The gelling agent of the present invention can cause gelling of for example, hydrophobic or non-polar liquids such as toluene, hexane, pentane, octane, Isopar, Magiesol available from Magie Brothers, and more specifically, the gelling agent, or component is useful for the gellation of inks. With the inks of the present invention there can be generated excellent developed images on plain and coated papers with acceptable image permanence, excellent projection efficiency on transparencies without needing a post fusing step, and excellent crease resistance, and wherein the inks possess acceptable, and in embodiments superior lightfastness, and superior waterfastness. Moreover, in embodiments of the present invention there is enabled the elimination, or minimization of undesirable paper curl since water need not be present in the invention inks, and it is preferred that there be an absence of water, and since water is preferably not present in the inks a dryer can be avoided thereby minimizing the cost of the acoustic ink jet apparatus and process. Furthermore, with the present invention in embodiments there is enabled inks with a low viscosity, for example from about 1 centipoise to about 10 centipoise at a temperature of for example, from about 40.degree. C. to about 125.degree. C., and preferably from about 40.degree. C. to about 70.degree. C. as measured by Carrim-Med CSL -100 rheometer TA Instrument, and which inks can be utilized at low jetting temperatures with an acoustic printing device, for example low temperatures of less than about 130 degrees Centigrade, and more specifically from about 50.degree. C. to about 125.degree. C.